There have been few studies quantifying
litterfall, standing litterstock and gross litter decomposition
following forest conversion to plantation
crops such as cocoa. Additionally, an assessment of
changing processes occurring in forest floor litter
systems with plantation age is lacking. We investigated
litterfall production, standing litter changes and
litter decomposition along a chronosequence of
shaded cocoa farm fields (secondary forest, 3, 15
and 30-year-old) in the moist semi-deciduous forest
belt in the Ashanti Region of Ghana in West Africa
over 24 months. Mean annual litterfall production
differed significantly among study sites and ranged
from 5.0 to 10.4 Mg DM ha−1. Similarly, standing
litter differed significantly between land-use /plot ages.
The results showed significant differences in quality
between litter from forest and litter from cocoa plantations. Litterfall from forests had higher concentrations
of nitrogen and lower concentration of soluble
polyphenols and lignin compared to litter from cocoa
systems. Monthly decomposition coefficients (k) estimated
as k ¼ ðA ðL1 L0ÞÞ= L1 þ L0 ðð Þ=2Þ, where
A is litterfall production during the month, L0 is the
standing litterstock at the beginning of the month and
L1 is the standing litterstock at the end of the month.
Annual decomposition coefficients (kL) were similar in
cocoa systems (0.221–0.227) but higher under secondary
forests (0.354). Correlations between litter quality
parameters and the decomposition coefficient showed
nitrogen and lignin concentrations as well as ratios that
include nitrogen are the best predictors of decomposition
for the litters studied. Our results confirm the
hypothesis that decomposition decreases following
forest conversion to shaded cocoa systems because of
litter quality changes and that decomposition rates
correlate to litter quality differences between forest and
cocoa ecosystems. The study also showed that standing litter pools and litterfall production in recently converted
cocoa plantations are low compared to secondary
forests or mature cocoa systems. Management
strategies involving the introduction of upper canopy
species during plantation development with corresponding
replacement of tree mortality with diverse
fast growing species will provide high quality and quantity litter resources.